On Fri, Mar 04, 2022 at 01:59:14PM +0000, Marc Zyngier wrote:
> Now that we properly account for interrupts taken whilst the guest
> was running, it becomes obvious that there is no need to open
> this accounting window if we didn't exit because of an interrupt.
>
> This saves a number of system register accesses and other barriers
> if we exited for any other reason (such as a trap, for example).
>
> Signed-off-by: Marc Zyngier <m...@kernel.org>
Acked-by: Mark Rutland <mark.rutl...@arm.com>
Mark.
> ---
> arch/arm64/kvm/arm.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index fefd5774ab55..f49ebdd9c990 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -887,9 +887,11 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
> * context synchronization event) is necessary to ensure that
> * pending interrupts are taken.
> */
> - local_irq_enable();
> - isb();
> - local_irq_disable();
> + if (ARM_EXCEPTION_CODE(ret) == ARM_EXCEPTION_IRQ) {
> + local_irq_enable();
> + isb();
> + local_irq_disable();
> + }
>
> guest_timing_exit_irqoff();
>
> --
> 2.34.1
>
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